BrowserActivity.kt

viewModel.command.observe(this, Observer {
    when (it) {
        is BrowserViewModel.Command.Refresh -> webView.reload()
        is BrowserViewModel.Command.Navigate -> webView.loadUrl(it.url)
        is BrowserViewModel.Command.DialNumber -> {
            val intent = Intent(Intent.ACTION_DIAL)
            intent.data = Uri.parse("tel:${it.telephoneNumber}")
            launchExternalActivity(intent)
        }
        is BrowserViewModel.Command.SendEmail -> {
            val intent = Intent(Intent.ACTION_SENDTO)   
            intent.data = Uri.parse(it.emailAddress)
            launchExternalActivity(intent)
        }
        is BrowserViewModel.Command.SendSms -> {
            val intent = Intent(Intent.ACTION_SENDTO, Uri.parse("smsto:${it.telephoneNumber}"))
            startActivity(intent)
        }
    }
})